[gardening] Unmark language/vm/optimized_stacktrace_test

Re-enable language/vm/optimized_stacktrace_test to determine whether it is still a flaky issue.

Issue: https://github.com/dart-lang/sdk/issues/28276
Issue: https://github.com/dart-lang/sdk/issues/30198
Change-Id: I4b63e38f130f8320dc38564129a67b08ac5f1866
Reviewed-on: https://dart-review.googlesource.com/c/88450
Commit-Queue: Martin Kustermann <kustermann@google.com>
Auto-Submit: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
diff --git a/tests/language_2/language_2_kernel.status b/tests/language_2/language_2_kernel.status
index 8ac22ba..292b4c8 100644
--- a/tests/language_2/language_2_kernel.status
+++ b/tests/language_2/language_2_kernel.status
@@ -636,8 +636,6 @@
 vm/causal_async_exception_stack2_test: SkipByDesign
 vm/causal_async_exception_stack_test: SkipByDesign
 vm/closure_memory_retention_test: Skip # KernelVM bug: Hits OOM
-vm/optimized_stacktrace_test: Crash
-vm/optimized_stacktrace_test: Skip # Issue 30198
 vm/reflect_core_vm_test: SkipByDesign
 vm/regress_27671_test: Skip # Unsupported
 vm/regress_29145_test: Skip # Issue 29145